Aminogroup-containing polysiloxanes have excellent thermal stability together with water repelling, anti-foaming and interface properties such as surface lubrication, and they are therefore used in a wide variety of different fields. Conventionally, these compounds were manufactured by heating one or more cyclic organopolysiloxanes with aminopropyldisiloxane in a ring cleaving reaction in the presence of a compound containing an alkali metal such as an alkali metal oxide, alkali metal hydroxide, alkali metal alkoxide, alkali metal aryloxide or alkali metal silanolate, a quaternary ammonium compound, or a quaternary phosphonium compound.
In the aforesaid manufacturing method, however, the viscosity of the reaction solution increased sharply during the reaction. This rendered the reaction system non-uniform so that a reaction product of uniform viscosity could not be obtained, and a gel-like substance was also partly formed. It was therefore difficult to manufacture an aminogroup-containing polysiloxane of uniform quality.
To overcome this disadvantage, a method has been proposed wherein a cyclic polyether is added in the aforesaid manufacturing process (Japanese Tokkai Hei 3-95227:Published unexamined application).
However, this cyclic polyether (of the crown polyether type) is costly, and the cost of manufacturing the aminogroup-containing polysiloxanes therefore increased.
After carrying out exhaustive studies, the inventors discovered that aminogroup-containing polysiloxanes could be easily manufactured by heating and reacting a specific cyclic organopolysiloxane with a specific aminoalkylpolysiloxane in the presence of a basic catalyst.